Remove the lightning app code #25742

Job	Run time
build-packages / init	4s
build-packages / build-packages (lightning)	22s
build-packages / build-packages (fabric)	27s
build-packages / build-packages (pytorch)	21s
install-pkg (ubuntu-22.04, fabric, 3.8)	2m 9s
install-pkg (ubuntu-22.04, fabric, 3.11)	2m 3s
install-pkg (ubuntu-22.04, pytorch, 3.8)	2m 12s
install-pkg (ubuntu-22.04, pytorch, 3.11)	1m 45s
install-pkg (ubuntu-22.04, lightning, 3.8)	1m 52s
install-pkg (ubuntu-22.04, lightning, 3.11)	1m 46s
install-pkg (ubuntu-22.04, notset, 3.8)	1m 46s
install-pkg (ubuntu-22.04, notset, 3.11)	1m 57s
install-pkg (macOS-12, fabric, 3.8)	1m 12s
install-pkg (macOS-12, fabric, 3.11)	1m 15s
install-pkg (macOS-12, pytorch, 3.8)	1m 13s
install-pkg (macOS-12, pytorch, 3.11)	1m 1s
install-pkg (macOS-12, lightning, 3.8)	1m 25s
install-pkg (macOS-12, lightning, 3.11)	1m 9s
install-pkg (macOS-12, notset, 3.8)	1m 6s
install-pkg (macOS-12, notset, 3.11)	1m 9s
install-pkg (windows-2022, fabric, 3.8)	2m 15s
install-pkg (windows-2022, fabric, 3.11)	2m 55s
install-pkg (windows-2022, pytorch, 3.8)	2m 6s
install-pkg (windows-2022, pytorch, 3.11)	2m 6s
install-pkg (windows-2022, lightning, 3.8)	2m 58s
install-pkg (windows-2022, lightning, 3.11)	3m 1s
install-pkg (windows-2022, notset, 3.8)	4m 41s
install-pkg (windows-2022, notset, 3.11)	2m 23s
	48m 39s

Provide feedback